Signaling system for multiplex telephone-circuits.



B. GHERARDL SIGNALING SYSTEM FOR MULTIPLEX TELEPHONE CIRCUITS.

ARPLICATION FILED NOV. 24.1916- I Patented Dec. 25, 19.17.

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INVENTOR ATTO R N EYaS' B. GHERARDI.

SIGNALING SYSTEM FOR MULTIPLEX TELEPHONE CIRCUITS.

APPIICAIION FILED NOV.24. 191s Patented Dec; 25, 1917.

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'Q'INVENTOR fiamrofi lzerardz A TORNEYJ B. GHERARDJ. SIGNALINGSYSTEM'FOR MULUPL TELEPHONE cmcuns,

I APPLICATION FILED N6v.24. 1916. 1,251,364. Patented Dec. 25,1911.

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- 'INVENTOR aw/ x2 (E /Mam fl w, ATToRNEYs UNITED STATES PATENT OFFICE.

BANCROFT GHERARDI, OF BAYHEAD, NEW JERSEY, ASSIGNOR TO AMERICAN TELEPHONE AND TELEGRAPHCOMPANX, A CORPORATION OF NEW YORK.'

SIGNALING SYSTEM FOR MULTIPLEX TELEPHONE-CIRCUITS.

To all whom it may concern Be it known that I, BANGROF'I GHERARDI,residing at Bayhead, in the county of Ocean and State of New Jersey,have invented certain Improvements in Signaling Systems for.

Multiplex Telephone-Circuits, of which the following is a specification.

This invention relates primarily to a s gnaling system for use inconnection with multiplex telephone systems, as for example the systemin Which several telephone conversations may be carried simultaneouslyover the same wire or pair of wires by means of carrier currents similarto those employed in wireless telephony and wireless telege raphy.

By means of such systems two or more simultaneous telephoneconversations-may be carried on over a single telephone trunk circuit,but to utilize such a system it is-necessary to have means .fortransmitting between the two terminals of this multiplexed telephonetrunk signals individual to eachseparate telephone channel, so that, forexample, when any conversation is completed, that fact may be made knownat both ends of'the trunk circuitat each end thereof a number of localsignaling circuits equal to the number of conversation channels, theselocal signaling circuits at each end being controlled and kept inassociation with each other by a signaling wire or path having at itstwo ends switching mechanisms operating in synchronism to connect thecorresponding local signaling circuits simultaneously with the two endsof the signaling wire. The signaling wire or path referred to abovemight be a separate wire, or it might be one of the channels passingover the telephone trunk which would be assigned to that purpose andwhich might otherwise have been used for a telephone conversation; or itmight be an Specification of Letters Patent.

Patented Dec.25,1917.

Application filed November 24, 1916. Serial No. 133,177.

ordinary telegraph circuit simplexed or composited on the telephonetrunk or any other means of passing electric currents. I For thepurposes of the illustration which I give below, I have shown the systemoperating with a separate signaling wire, this'wire being du'plexed andbeing equipped at either end with the synchronous device already referred to.

The construction and operation of the signaling system may. be morereadily understood by reference to the appended drawings,

Figures 1 to 3 inclusive of which, when placed side by side in numericalorder, illustrate such portions of the complete circuit arrangement andapparatus as is necessary for. a full understanding of the invention.For convenience it has been assumed that each trunk is equipped withtranslators so.

that a plurality of conversations can be carried on simultaneously. Thedrawing shows but one trunk circuit but it is obvious that any number oftrunks can be employed with the signaling method outlined. Some of thesetrunks might be phantom circuits. In order, however, to make thedescription of the circuit clearer but one arrangement has been shown.On this drawing X and Y represent two ofiices connected by a pluralityof trunk circuits similar to T-1, each provided with translators E, F,

-L, L and retardation coils I and I. Across the ends of each set ofretardation coils are bridged the/polarized relays 6 and (3 at ofli- Vces X and Y respectively.

The two ends of the signaling wire S are connected to interrupters K andK, interrupter K having a transmitting section T and a receiving sectionB, interrupter K having, correspondingly, sections T and R. Theinterrupters as conventionally shown in the drawing, are preferably thewell-known multiplex distributers that are employed in connection withmultiplex printing telegraph systems and are provided with a synetc.,whereby" a plurality of simultaneously operating tallc chronizing device(not shown) by means of which synchronism is automatically maintainedbetween the brushes 6., cl, 6 and Z), d, 6. These brushes revol econtinuously and maize contact with the segments or terminals of theinterrupters. The local signaling circuits A, B, etc. and A, B, etc,associated with the various telephone circuits which may besimultaneously extended over trunk Tl and individual thereto, arerepresented on corresponding transmitting terminals 8 and 8 and oncorresponding receiving terminals S and 9.

In the particular arrangement shown, the local signaling apparatusconsists of relays and lamps such as are usually employed in commonbattery signaling systems, and the structure and operation of thecircuits and apparatus at ofiice X are identical with the structure andoperation of the circuits and apparatus at oiiice Y. For convenientreference the corresponding parts at the two otiices are designated bythe same reference numerals, the numerals at office X without and thoseat oliice Y with primes.

With this general description in mind the invention. can now be fullyunderstood from the operation thereof, which is as follows:

Assuming that the operator at oliice X desires to establish a connectionto oliice Y, using the conversation channel terminating at L the plug Pis inserted in jack J thereby connecting battery 24 through thesupervisory lamp signal :0 and the 32-ohm winding of relay 1 to ground,causing the lamp to be illuminated; also relay 1 is energized andthrough its contact 39 connects battery to the winding of relay 2causing it to operate. It should be noted that contacts Ill-39 of relay1 are of the make-break type so that when the springs are operated oneof the contactsis made before the other is broken. T herei'orc, at themoment when contact 39 is made a momentary circuit is established frombattery 24 through contacts 39 and 11 over conductor 12 to the windingof relay 5 to ground. This momentary impulse causes relay 5 to operate.and close contact 13 which closes a circuit from battery 24, throughresistance 14, over conductor 1:), through contact 13, through thewinding of relay 5, to ground, this latter circuit causing the relay toremain energized after it has been operated by the momentary impulsecaused by the operation of relay l, The operation of relay 5 also causesContact 16 to close. which connects segment f) 1}, through Contact 42 ofrelay 1, now onergized, to the negative pole of battery, 110. vlnterruptors K and K are operating in synchronism and therefore whilethebrushes and a" of interrupter K re in contactwith terminals 3 and, 8,the brushes Z) and d of interrupter K. are in contact with. thecorinterrupter K over conductors -and incisor.

responding terminals 7 and 8 respectively. During the time thesecontacts are closed, negative current flows from battery 110, throughcontact 18 of relay 1, over conductor 17, through contact 16 of relay 5,and conductor 35, to segment 8, brush Z), over line S through winding ofrelay 6 and artificial line L to ground, operating the polarized relay 6at olfice Y, thereby closing the circuit of relay at from battery 24',through winding and contact 20 of relay 4 over conductor 21' to segment9 of inter rupter K, to brush 6, over conductor 22, through contact 38of polar relay 6 to the ground side of battery 24; said circuit causingrelay 4 to be energized The operation of relay 4 closes contact therebycompleting a locking circuit for relay 4 from ground contact 40, windingof 4, upper normal contact of relay 3, to battery 24. Contact 40 alsoconnects ground over eonductor 26 to contact 27 of relay 2, overconductor 28 to the line lamp S of the conversation channel terminatingat L to battery 24; said circuit causing the lamp to light and therebynotify the operator at ofiice Y that she is wanted on that particularcircuit.

At the instant when brush 1) of interrupter K is in contact with segment8, brush (Z of the same interrupter is in contact with segment 7. At theinstant this latter circuit is closed, ground is connected from brush (5to segment 7 over conductor 29 to the winding of relay 5 which isthereby short-circuited and caused to release and open its contacts 13and 16. The object in opening contacts 13 and 16 is for the purpose ofpreventing further operation of the circuits closed bythesc contacts andalso to prevent an unnecessary waste of current.

The operator at office Y inserts plug P in jack J of the circuitterminating at L in answer to the signal received, when battery 2% isconnected through. the supervisory signal lampw, through the windings ofrelay 1 to ground, causing relay 1 to operate. The lamp a? is notlighted at this time because contact 25 of relay 4 has disconnected theground that has been connected to the 32-ohm winding of relay 1 overconductor 36, and the circuitpf lamp a1 passes through the 400-ohmwinding of relay .1. The operation oi relay 1 closes contacts 39 and 18'and establishes the following circuits: from battery 24: through con- 3'as follows Ground .is connected through contact 30 of relay 2 throughthe winding of relay 3', through contact 32 through contact 41 of 5relay 4' which is now energized; over conductor 21, through segment, 9of interrupter K, over conductor 22 and alternate contact 38 of polarrelay 6 to ground. Relay 3, however, is not operated because its circuitat this time is grounded at both ends.

At the instant when relay 1 operates, a momentary circuit is establishedas follows:

over conductor 33,

from battery 24 through contacts 39 and 1 11' of relay 1, over conductor12, and through the winding of relay 5 to ground, causing this relay tooperate and close contacts 13 and 16. Contact 13 closes a'circuit frombattery 24', through resistance 14,

over contact 13 and through the winding of relay 5' to ground, causingthis relay to remainoperatedafter it has been energized by the momentaryimpulse created by the operation of relay 1'. Contact 16 closes thefollowing circuit: from the negative pole of battery 110', throughcontact 42 of relay 1, (now energized), over conductor 17 throughcontact 16' of relay 5, over conductor to segment 8 through brush 6,over the signaling wire S, through the winding of polar relay 6, andthrough the artificial line L to ground, causing polar relay 6 tooperate and connect ground through its contact 38, over con; ductor 22,to brush e of interrupter K, to segment 9, through contact 20 andwinding of relay 4, to battery 24, causing relay 4 to operate. Theoperation of relay 4 closes contacts and 41 and opens contacts 20 and 25which establish the following circuit change: Contact 25 opens theground which has been connected to the 32-ohm winding of relay 1, overconductor 36. The removal of this ground increases the resistance inseries with the lamp 0: so that it will not eceive enough current toremain illuminated. Lamp a; is therefore extinguished, which indicatesto the operator at oflice X that the operator at office Y has answeredthe. call.

At the same instant that brush 6 on interrupter K was in contact withsegment 8, brush (1 was also in contact with segment 7'. As soon as thislatter contact is made, ground is connected to the winding of relay 5thereby shortcircuiting it and causing it to release and open itscontacts 13 and 16 thus reventing the further operation of the circuitscontrolled by these contacts.

From the foregoing it. will be seen that the operator at ofiice Y inanswering the sig- 60 nal by inserting plug P in jack J causes a cycleof operations which results in the extinguishing of the supervisorysignal lamp or at ofiice X, therehuinforming the operator at that officethat the operator at oflice Y 6? has responded. Assuming now that the ofrelay 3 of interrupter K,

operator at office X removes the plug P from jack J associated withcircuit L this operation releases relay 1 which, while releasing,momentarily establishes through contacts 39 and. 11 the followingcircuit: from battery 24 through contacts 39 and 11,.over conductor 12,through the winding of relay 5 to ground, causing relay 5 to operateand-close its contacts 13 and 16. Contact 13 connects battery 24,,through resistance 14, and over conductor 15 and contact 13, through theWinding of relay 5 to ground, causing it .to remain operated. Contact 16closes the following circuit: from the positive pole of battery 110,through contact 18 of relay 1, over conductor 17, through contact 16 ofre lay 5, over conductor 35, to segment 8rof interrupter K, throughbrush Z, over the signaling wire S, through the winding of polar relay-6, through the artificial lineL to ground. The operation of relay 6closes the following circuits through its contact 37. From groundedbattery 24 through contact 37, over conductor 22 to brush 6' of inter- Irupter K, to segment 9, over conductor 21', through contact 41 of relay4', (which is now energized), over conductor 33, through contact 32 ofrelay 3', through the winding of relay 3, through contact 30 of relay 2toground; said circuit causing relay 3 to operate. Contact 34 of thisrelay opens the locking circuit from battery 24, through the winding ofrelay 4, over contact 25 to ground, thereby causing relay 4 to release.Contact 43 of relay 3 connects battery 24 to its winding through contact30 of relay 2 to'ground, thereby causing relay 3 to remain opera-ted.When relay 4 is released, ground is connected through its contact 25,over conductor 36, to the-32-ohm winding of relay 1. The circuit thusestablished causes sufficient current to flow from battery 2 1 to lampat through the 32-ohm winding of relay 1 so that the lamp will belighted, thereby indicating to the operator at ofiice '1 that theoperator at-ofi'ice X has removed her plug from the circuit.

The operator at office Y therefore removes plug P from jack J, whichoperation releases relay 1. Relay 1 in releasing establishes thefollowing circuits: battery 24' is momentarily connected throughcontacts 39' and 11, over conductor 12, through the Winding of relay 5to ground, thereby causing this relay to operate. Contact 13 of relay 5connects battery 24, through resistance 14,.through the winding of relay5 to ground, causing it to remain operated. Contact 16 of relay 5 closesthe following circuit: from the positive pole of battery 110, throughcontact 18- of relay 1, over conductor 17, through contact 16 of relay5', over conductor 35, to segment 8 of inter- 'rupter K, through brush6', over the sigrelay (3, and through the artificial line L to ground.The operation of polar relay 6, however, at this time does not cause anysignals to be operated because its contacts connect battery 2st overconductor 22, through brush 6 of interrupter K, to segment J, and, sincerelay 4 has been released by the removal of the plug P, over contact 20and the winding of relay at to the same side of the battery, so that noflow of current will result. This completes the cycle of signaloperations associated with making and disconnecting a circuit over lineL between ottices X and Y. The operation for the other circuits shownwill be precisely the same.

While for purposes of illustration 1 have shown and described myinvention as embodied in a specific form, it will be understood that theinvention is not limited to the specific arrangements herein set forth,since it is capable oi numerous other embodiments falling within thescope of the appended claims and may be applied to electrical systems,other than telephone systems when a similar system of signals or controlis desirable.

\Vhat is claimed is:

1. The combination of a plurality of operating circuits, a common trunkover which said circuits may be simultaneously extended between twopoints, a coiuluctive path distinct from but common to said circuitsalso extending between said points, a plurality of local translatingcircuits individual to said operating circuits at said points, andswitching apparatus at the opposite ends of said conductive path forsuccessively con necting corresponding local translating circuits to thetwo ends of said conductive path.

2. In a telephone system, the combination of a plurality of telephonecircuits, a common telephone trunk over which said circuits may besimultaneously extended between two ofiices, a plurality of local translating circuits individual to said telephone circuits at each ofsaidofiices, said local translating circuits at one othce correspondingrespectively to said local translating circuits at the other ofiice aconductive path extending between said ofiices, and switching apparatusat the opposite ends of said conductive path for successively connectingcorresponding local translating circuits to the two ends of saidsignaling path.

3. In a telephone system, the combination of a plurality of trunksextending- -letwecu two oilices, a plurality of talking circuitssimultaneously extending over each trunk, a plurality of local signalingcircuits individual to said talking circuits at each of said oiiices, asignaling path extending between said ofiices, and switching apparatusat the opposite ends or said signaling path for Licensee successivelyconnecting the corresponding local signaling circuits to the two ends ofsaid signaling path.

4. In a telephone system, the combination of a plurality of trunksextending between two ottices, a plurality of talking circuitssimultaneously extending over each trunk, a plurality of local signalingcircuits, one for each of said talking circuits and individual theretoat each of aid oflices, a signaling path common to the plurality of saidtrunks extending between said OlllCBS, and switching apparatus at theopposite ends of said signaling path for successively connecting thelocal signaling circuits associated with a plurality of trunks to thesignaling path.

5. The combination of a plurality of operating circuits, a common trunkover which said circuits may be simultaneously extended between twopoints, a common signaling path for said operating circuits, a pluralityof local signaling circuits each in"- dividual to one of said operatingcircuits, and switching apparatus operated at the opposite ends of saidsignaling path for successively connecting corresponding local signalingcircuits to the two ends of said signaling path.

6. In a telephone system, a plurality of telephone circuits, a commontrunk over which said circuits may be simultaneously extended betweentwo points, a common signaling path for said telephone circuits,'a localsignaling circuit individual to each of said telephone circuits at eachof said ofiices, and automatic means operating to successively connectcorresponding local signaling circuits with each other over said commonsignaling path.

7. In a. signaling system, the combination of a plurality of operatingcircuits, a

common trunk over which said circuits may be simultaneously extendedbetween two points, a signaling path common to said op erating circuits,local signaling circuits at each of said points associated with saidoperating circuits, switching apparatus at each end of said signalingpath for successively connecting corresponding local signaling circuitsto the ends of said common signaling path, switching mechanism at saidpoints associated with said operating circuits. and means under thecontrol of said switching mechanism for signaling over said commonsignaling path and said local signaling circuits.

8. In a signaling system, the combination of a pin 'ality of operatingcircuits, a common trunk over which said circuits may be simultaneouslyextended between two ollices; a signaling path common to said operatingcircuits. local signalin circuits at each of said ollices associatedwith said operating circuits and individual thereto,

switching apparatus at each end J said signaling path for successivelyconnecting corresponding local signaling circuits to the ends of saidcommon signaling path, and. electromagnetic switching mechanismassociated with said operating circuits and with said local signalingcircuits for signaling ovei said common signaling path and said localsignaling circuits.

9. The combination of .1 plurality of operating circuits, a common trunkover which said circuits may be extended between two points, a signalingpath between said points, a signaling circuit individual to each of saidoperating circuits at each of said points, relays associated with theends of saidpath, and switching apparatus at the opposite ends of saidsignaling path for successively connecting corresponding local signalingcircuits to said relays 10. In a signaling system, the combination of aplurality of trunks extending be tween two points, a plurality ofsimultaneously operating communication circuits extending over eachtrunk and common thereto, a signaling circuit at each'point individualto each communication circuit, a signaling path common to a plurality oftrunks extending between said points, and means to successively connect.the local signaling circuits corresponding to the communication circuitsof a plurality of trunks to the ends of said signaling path.

In testimony whereof, I have signed my name to this specification in thepresence of two subscribing witnesses, this twenty-' first day ofNovember, 1916.

BANOROFT GHERARDI. Witnesses:

SAMUEL RAsMIsAN, R. S. SUTLIFFE.

